I didnt click on the link, but I spent a bunch of time playing the sponsor game for 15 years. That included drag racing snowmobiles and circle dirt track racing. The sled part was pretty tough going due to the fact that you dont have several thousand people watching you every week for 25 weeks out of the year. It was VERY hard to get cash, the better route was a parts allowance and parts at dealer cost.
The stock car racing was much easier and almost all of them were cash deals.
Bottom line is you need to be professional, have a nice portfolio and be able to sell yourself and explain how they will get a return on their advertising dollars. Things like attendance numbers, number of events you plan on attending, and how far away people come from to go to these events are all good info to present.
Now get ready to get rejected about 90% of the time
Eric